[Zope] WebDav & MS Word problem - CANNOT SAVE

Any idea why saving on Zope (as WebFolder) does not work from MS Word 2000? When zope is asking for passwrd, I log in as the Zope superuser, so the prob is not there. I've got Zope working fine as a WebDav server, when moving files via NT Explorer. But trying to work straight from MS Word is read-only. It seems the files are always opened read-only from Word when they are stored on (Zope) WebDav server. The file props don't say it's readonly though (regular NT fileprops). Another MS quirk? "WebDav support", but not from Office? Or with servers other than IIS? Let me be wrong... Thanks, Petri